Hello,
Not sure whether I should come here or to the linux amdgpu developers for this one?
With both the current simcity and simcity 4 games there is an issue where the lighting is not correct after having switched from the AMD drivers to the AMDGPU open source drivers on my linux host where the Win7 Pro VM resides. The screenshots attached probably provide a better explanation than I can write for this one. I had not issues with the previous versions of the ati-drivers versions 15.12, 15.9, etc.
My host is running kernel 4.9.33 and Workstation 12.5.7.